58 ie (S. ROSS 
SUMMARY 
1. The intracellular origin of the axone of the large nerve cell 
of the crayfish consists of a large number of neurofibrillae widely 
distributed in the cytoplasm and almost surrounding the nucleus. 
The fibrillae converge to form an intracellular axone deep within 
the cell body, whereas in some invertebrates and in most of the 
vertebrates the fibrillae converge to an axone hillock near the 
periphery of the cell. 
2. By means of intravitam staining some evidence of the 
probable existence of neurofibrillae in living cytoplasm is 
obtained. 
3. The Golgi internal reticular apparatus was not demon- 
strated. 
4. Nissl bodies were not demonstrable in living cells, but are 
evident in fixed and stained cells. The bodies are probably 
artefacts, although there is no reason to doubt the chemical 
entity of the Nissl (chromidial) substance. 
5. Mitochondria are readily demonstrable in the cell bodies 
and along the course of the fibers. 
6. The trophospongium shows connection with the sheath 
cells, and may be traced as very delicate filaments, in section, 
penetrating even to the center of some cells. 
Drake University, 
Des Moines, lowa. 
LITERATURE CITED 
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Anat. u. Ontog., Bd. 31, S. 473-494. 
Bayuiss, W.M. 1915 Principles of general physiology. London. 
Brenstey, R. R. 1911 Studies on the pancreas of the guinea-pig. Am. Jour. 
Anat., vol. 12, pp. 297-388. 
Betue, ALBRECHT 1895 Studien itiber das Centralnervensystem von Carcinus 
maenas nebst Angeben iiber ein neues Verfahren der Methylenblau- 
fixation. Arch. f.mikr. Anat., Bd. 44, S. 579-622, Tafel 3. 
1897 Das Nervensystem von Carcinus maenas. Arch. f. mikr. Anat., 
Bd. 50, 8. 460-546, Tafel 6. 
1900 Ueber die Neurofibrillen in den Ganglionzellen von Wirbel- 
thieren und ihre Beziehungen zu den Golginetzen. Arch. f. mikr. 
Anat., Bd. 55, S. 513-544, Tafel 3. 
